This application is related to patent applications entitled xe2x80x9cSLIDE VALVE AND SUCTION BASED SPONTANEOUS INFLATION INHIBITOR IN A PUMP FOR AN INFLATABLE PROSTHESISxe2x80x9d and xe2x80x9cSWITCH BASED SPONTANEOUS INFLATION INHIBITOR IN A PUMP FOR AN INFLATABLE PROSTHESIS,xe2x80x9d which were filed concurrently herewith.
This invention generally relates to a pump for inflating a prostheses and more particularly to a pump and valve assembly including a diaphragm which inhibits spontaneous inflation of the prosthesis.
One common treatment for male erectile dysfunction is the implantation of a penile prosthesis. Such a prosthesis typically includes a pair of inflatable cylinders which are fluidly connected to a fluid reservoir via a pump and valve assembly. The two cylinders are normally implanted into the corpus cavernosae of the user and the reservoir is typically implanted in the user""s abdomen. The pump assembly is implanted in the scrotum. During use, the user actuates the pump and fluid (typically liquid) is transferred from the reservoir through the pump and into the cylinders. This results in the inflation of the cylinders and thereby produces the desired penis rigidity for a normal erection. Then, when the user desires to deflate the cylinders, a valve assembly within the pump is actuated in a manner such that the fluid in the cylinders is released back into the reservoir. This deflation then returns the penis to a flaccid state,
With inflatable penile prostheses of current designs, spontaneous inflation of the cylinders is known to occasionally occur due to inadvertent compression of the reservoir. Specifically, this inadvertent compression results in the undesired introduction of fluid into the cylinders. While this does not create a medical or physical problem, such inadvertent inflation can be uncomfortable and embarrassing for the user. This undesirable condition is further described below with reference to a particular prosthetic design.
With reference to FIG. 1, a known pump and valve assembly 8 for use in a penile prosthesis includes a fluid input 10 that is coupled at one end to a reservoir (not shown) and to a housing 12 at its opposite end. Also connected to the housing 12 is a fluid output 14 which, in turn, is connected at its other end to a pair of cylinders (not shown). Linking the fluid input 10 and the fluid output 14 to each other is a common passageway 33, which itself contains a valve assembly that is described in greater detail below. Common passageway 33 is also in fluid communication with a pump bulb 18 that is used to move fluid from the reservoir (not shown) to the cylinders (not shown) in order to inflate the cylinders. The valve assembly located within common passageway 33 includes a reservoir poppet 20 which is biased against a valve seat 24 by a spring 28 and a cylinder poppet 22 which is biased against a valve seat 26 by a spring 30. The springs 28 and 30 are sized so as to keep the reservoir poppet 20 and the cylinder poppet 22 biased against each respective valve seat 24 and 26 under the loads that are encountered when the reservoir is pressurized to typical abdominal pressures.
When the user wishes to inflate the cylinders, pump bulb 18 is squeezed so as to force fluid from the pump bulb 18 into the common passageway 33. The resulting fluid flow creates a fluid pressure on reservoir poppet 20 which compliments the force of the spring 28 to hold the reservoir poppet 20 against valve seal 24. The fluid flow also causes compression of the spring 30, and thereby opening cylinder poppet 22. As a result, the fluid travels out through fluid output 14 and into the respective cylinders.
When the user releases the pump bulb 18 a vacuum is created, thus pulling the poppet 22 back against valve seat 26 (aided by spring 30) and simultaneously pulling the reservoir poppet 20 away from its valve seat 24, against the spring 28. As a result, fluid from the reservoir is thus allowed to flow through the fluid input 10 to the common passageway 33, passing around the reservoir poppet 20. Fluid then will freely flow into the vacuous pump bulb 18. Once the pump bulb 18 has been filled, the negative pressure is eliminated and the reservoir poppet 20 returns to its normal position. This pumping action of the pump bulb 18 and valve assembly is repeated until the cylinders are fully inflated as desired.
To deflate the cylinders, the user grips the housing 12 and compresses it along the axis of reservoir poppet 20 and cylinder poppet 22 in a manner such that the wall 13 of the housing 12 contacts the protruding end 21 of the reservoir poppet 20 and forces the reservoir poppet 20 away from valve seat 24. This movement, in turn, causes the reservoir poppet 20 to contact cylinder poppet 22 and force cylinder poppet 22 away from valve seat 26. As a result, both poppets 20 and 22 are moved away from their valve seats 21 and 26 and fluid moves out of the cylinders, through the fluid output 14, through common passageway 33, through the fluid input 10 and back into the reservoir.
Although the springs 28 and 30 are sized to provide sufficient tension to keep poppets 20 and 22 firmly abutted against valve seats 24 and 26 under normal reservoir pressures, it is possible for fluid pressure to exceed the force provided by the springs during heightened physical activity or movement by the user. Specifically, this activity or movement can apply excess pressure to the reservoir. Such excessive pressure on the reservoir may overcome the resistance of the spring-biased poppets 20 and 22 and thereby cause a spontaneous inflation of the cylinders. Encapsulation or calcification of the reservoir can sometimes occur in a patient. This encapsulation could lead to a more snugly enclosed reservoir, thus increasing the possibility of providing excess pressure on the reservoir and the likelihood of spontaneous inflation.
As such, there exists a need to provide a prosthetic penile implant having a spontaneous inflation prevention mechanism that is reliable and easy to operate.
The present invention includes a penile pump having a dual poppet arrangement wherein the poppets act as check valves or flow valves. Each poppet is spring-biased against a valve seat, and under normal circumstances, only allows positive fluid flow when a pump bulb is engaged. To prevent spontaneous inflation when an overpressurization occurs in the reservoir, the same reservoir pressure is utilized to seal the fluid output against itself or to seal one or both of the poppets against the valve seat. Thus, the fluid is prevented from reaching the cylinders and creating a spontaneous inflation. When the movement or activity generating the overpressure in the reservoir is released, the system will return to an equilibrium and allow normal operation. Even if overpressurization of the reservoir is occurring, the pressure generated by compressing the pump bulb will far exceed the level of overpressure. Thus, the poppets will open in the normal way, allowing fluid to flow to the cylinders.
The use of the overpressure in the reservoir itself to prevent fluid flow to the cylinders can be accomplished in a variety of formats. Each of these formats however, generally utilize a structure in fluid communication with the reservoir which is capable of restricting flow caused by reservoir overpressurization.
In a first embodiment, a bypass passageway is provided from the fluid input which terminates in an expansion chamber located directly behind the cylinder poppet. A portion of the housing forms a wall between this chamber and the cylinder poppet. This wall is larger in surface area than the surface area of the cylinder poppet exposed to the overpressure. Since the surface area of the wall is larger than the area of the poppet that contacts the valve seat, the same amount of pressure generated by the reservoir will cause a larger force to be applied by the chamber wall against the poppet than is applied against the poppet through the common passageway. Thus, the cylinder poppet is effectively sealed when an overpressurization occurs in the reservoir.
In another embodiment, the bypass passageway is similarly coupled to the fluid input, bypassing the poppets and terminating in an expansion chamber. The cylinder poppet passageway output leads into a termination chamber connected to the expansion chamber, The expansion chamber is larger than the cylinder poppet output. Located within the expansion chamber is a flexible diaphragm dividing the chamber into two portions. As overpressurization occurs in the reservoir, this pressure is directed through the bypass passageway and is applied to the diaphragm. This pressure causes the diaphragm to flex against the output of the poppet chamber, effectively sealing it. In this sealing position, the diaphragm prevents fluid from reaching the cylinders.
In yet another embodiment, a fluid bypass passageway is provided which connects the fluid input and a chamber which surrounds a portion of compressible tubing. The compressible tubing forms part of the output that leads from the cylinder poppet to the cylinders. As overpressurization occurs in the reservoir, this force is directed along the bypass passageway causing the flexible tubing to compress, thus effectively sealing it off. Once again this prevents fluid flow to the cylinders because the flexible tubing is part of the output.
In a further embodiment, a fluid bypass passageway is provided between the reservoir and a fluid return passageway. The fluid return passageway couples an expansion chamber to an intermediate chamber between the reservoir poppet and the cylinder poppet. A bypass check valve is included in the bypass fluid passageway and allows pressurized fluid to flow from the input chamber into the return passageway. A return check valve is provided within the return fluid passageway between the intermediate chamber and the point where the bypass fluid passageway intersects the return fluid passageway.
Thus, in an overpressure situation, pressurized fluid is allow to flow from the input chamber through the bypass fluid passageway and into the expansion chamber. The expansion chamber includes a flexible abutting wall which is caused to engage the cylinder poppet and to firmly seat it. In this situation, spontaneous inflation is avoided.
While spontaneous inflation is prevented, pressurized fluid is able to enter the intermediate chamber. When the pressure of the fluid in the reservoir and the input chamber is reduced, this pressurized fluid remains in the intermediate chamber. If the expansion chamber were just allowed to relax when fluid pressure in the reservoir is reduced, it may be possible for the pressurized fluid in the intermediate chamber to open the cylinder poppet and partially inflate the cylinders. Thus, by providing this configuration of a bypass fluid passageway and a return passageway with the appropriate check valves, the pressured fluid entering the expansion chamber will be caused to remain there until the fluid pressure in the intermediate chamber is reduced. When the pump bulb is actuated, sufficient pressure is generated to overcome the opposing force generated in the expansion chamber and the cylinder poppet is unseated.
In still another embodiment, a bypass fluid passageway and a return fluid passageway are provided wherein each includes a check valve as previously described. However, in this embodiment, both the bypass fluid passageway and the return fluid passageway are fluidly coupled to the input chamber. In addition, the return fluid passageway is coupled to the intermediate chamber. Located within the return fluid passageway between the intermediate chamber and the input chamber is a fluid resistor.
When an overpressurization situation occurs, pressurized fluid will enter both the expansion chamber and the intermediate chamber. As previously described, the expansion chamber will seat the cylinder poppet firmly against the opening. As fluid pressure is reduced in the reservoir and input chamber, the fluid resistor allows pressurized fluid from the intermediate chamber to bleed back to the input chamber. Thus, eventually, the fluid pressure within the immediate chamber will be lower than the fluid pressure within the expansion chamber. Once this occurs, the return check valve will open and the pressurized fluid within the expansion chamber can return to the input chamber. Due to the configuration of the return check valve and the fluid resistor, pressure levels within the expansion chamber will always be higher than pressure levels within the intermediate chamber and, as a result, the cylinder poppet will always be firmly seated.
In still yet another embodiment, a bypass fluid passageway and a return fluid passageway are provided wherein each is fluidly coupled to the input chamber. A check valve is placed within the bypass fluid passageway which only allows fluid to flow from the input chamber to the expansion chamber. Located within the return channel fluid passageway are a pair of fluid resistors placed on either side of a passageway into the intermediate chamber. When an over-pressurization situation occurs, pressurized fluid opens the bypass check valve and allows fluid flow through the bypass fluid passageway to the expansion chamber. This pressurized fluid then firmly seats the cylinder poppet. Pressurized fluid will also enter the intermediate chamber. When pressure is reduced in the reservoir and the input chamber the pressurized fluid trapped within the intermediate chamber is slowly able to bleed through a single fluid resistor into the input chamber. As fluid pressure is reduced in the intermediate chamber and the portion of the return fluid passageway located between the fluid resistors, the pressurized fluid within the expansion chamber is slowly able to bleed through the second fluid resistor and eventually into the input chamber.
In still another embodiment a bypass fluid passageway is provided that couples the input chamber to an expansion chamber. The intermediate chamber is also fluidly coupled to the bypass fluid passageway. A first fluid resistor having a relatively low fluid resistance is placed between the intermediate chamber and the bypass fluid passageway. A second fluid resistor having a higher impedance is placed between the expansion chamber and the intermediate chamber. A bypass channel is constructed around the second fluid resistor and includes a bypass check valve allowing fluid to flow from the bypass fluid passageway around the second fluid resistor and into the expansion chamber. When an over-pressurization situation occurs, pressurized fluid will be trapped within the expansion chamber and the intermediate chamber. When pressure is reduced, pressurized fluid is able to flow from the intermediate chamber through the low impedance fluid resistor through the bypass fluid passageway and into the input chamber. As pressure levels drop within the bypass fluid passageway pressurized fluid will eventually be able to flow from the expansion chamber through the high impedance fluid resistor and into the input chamber. This configuration also ensures that fluid pressure levels within the expansion chamber will always be higher than those within the intermediate chamber (except during actuation of the pump bulb). Thus, preventing spontaneous inflation.
In another embodiment, an input chamber is provided that is connected to the fluid input, prior to the point the fluid input engages the first poppet. At the output of the pump, a passageway leading from the cylinder poppet to the cylinders is caused to narrow in a throat region, which is located proximate the input chamber. When an overpressurization of the reservoir occurs this input chamber is caused to expand, thus forcing its outer walls to move outward. Outward movement of the outer walls effectively seals the throat portion, thus preventing fluid flow from the reservoir from reaching the cylinders.
In still yet another embodiment a separate problem is addressed. Namely inadvertent compression of the valve walls may lead to an unseating of the reservoir and/or cylinder poppet and possibly lead to spontaneous inflation. To prevent this it may be desirable to make the housing substantially more rigid. This can be accomplished by encasing the reservoir and cylinder poppets within a solid cylindrical membrane.
In most of the above outlined embodiments, the force generated by an overpressurization of the reservoir is used to prevent fluid flow into the cylinders.